1. Field of the Invention
The present invention relates to a high-frequency integrated circuit, and more particularly to a high-frequency integrated circuit which has a nonradiative dielectric waveguide and operates in a microwave band or in a millimeter wave band.
2. Description of Related Art
It is well known that dielectric strips can be arranged between a pair of conductive plates which are parallel to each other with a specified spacing to form a nonradiative dielectric waveguide which propagates an electromagnetic wave in the LSM01 mode or LSE01 mode. For example, if the dielectric strips are designed to be made of a dielectric material with a dielectric constant (.epsilon.r) of 2 such as fluororesin and to have a width b of 2.5 mm and a height a of 2.25 mm, the dielectric strips will form a nonradiative dielectric waveguide which propagates an electromagnetic wave in a band of 60 GHz. When these dielectric strips are put between two conductive plates, an electromagnetic wave which has a wavelength more than twice the height a hardly leaks from the dielectric strips. Therefore, an electromagnetic wave in LSM01 mode or in LSE01 mode is propagated along the dielectric strips without radiating, that is, with a small loss. Thus, such a nonradiative dielectric waveguide is suited to be used as a transmission line for a microwave band or a millimeter wave band.
Since it is possible to provide magnetic parts and semiconductor chips as well as dielectric strips between a couple of conductive plates, a circulator, an oscillator and the like which have a nonradiative dielectric waveguide can be formed. In this way, a high-frequency integrated circuit which operates in a microwave band or in a millimeter wave band can be produced.
In producing such a high-frequency integrated circuit, first, evaluation is conventionally carried out. For example, in producing an FM-CW radar, dielectric strips, magnetic parts and semiconductor chips are arranged between a pair of conductive plates for evaluation to form a circulator, an oscillator and so on. The conductive plates are connected to an evaluation terminal, and the characteristics of the whole circuit which is composed of the circulator, the oscillator, etc. are measured. Then, the dielectric strips, the magnetic parts and the semiconductor chips are dismounted from the conductive evaluation plates, and then these parts are rearranged between another pair of conductive plates to produce an integrated circuit.
However, in this method, it is difficult to rearrange the circulator, the oscillator, etc. in the same way to reproduce an integrated circuit with the characteristics as measured. In this method, it is impossible to evaluate and adjust the circulator, the oscillator, etc. individually. Therefore, the mass productivity of the integrated circuit is not good. Further, when the integrated circuit has a defect, and a part of the integrated circuit, for example, the circulator or the oscillator is exchanged, the change of the part may influence the whole circuit.